Biomedical subjects

N Murai

Publications and source records attributed to N Murai.

At least 73 records · Page 4Linked to original sources

PubMed1995

[Results of emergency coronary artery bypass surgery after failed coronary angioplasty].

In the past 7 years, 9 emergent or urgent coronary artery bypass operations after failed percutaneous transluminal angioplasty (PTCA) were performed among 947 (PTCA). Since the introduction of coronary perfusion catheter system for the support of coronary perfusion during PTCA we could reduce the number of emergent cases and these patients could be operated on semi-emergently and securely without endangering co-medical staffs in a hurry. It is also unnecessary to be on standby all the time when the PTCA is being undertaken. Two acute myocardial infarction cases died in the early phase of this study (operative mortality 22%) and none after the introduction of coronary perfusion system during PTCA.

Aged↗

PubMed1994

Synergism between CACGTG (G-box) and CACCTG cis-elements is required for activation of the bean seed storage protein beta-phaseolin gene.

Expression of bean seed storage protein phaseolin is under strict developmental control. Four distinct nuclear proteins recognize in vitro the proximal beta-phaseolin promoter (-295/+45) which confers spatial and temporal regulation of the native gene. Functional significance of these protein-binding sites was evaluated by substitution mutation of the motifs in the promoter, which was fused to GUS reporter gene, and subsequent transient gene expression assay using protoplasts from developing bean cotyledons. DNA-binding protein CAN binds three CANNTG motifs, CACGTG (-248/-243), CACCTG (-163/-158), and CATATG (-100/-95). Substitution mutation of the CACGTG motif, which is commonly known as G-box, reduced the -295 promoter activity by 75%, indicating that the G-box is a major positive cis-element. Mutation analyses also demonstrated that the CACCTG and CATATG motifs act as positive and negative cis-elements, respectively. Substitution mutation of all three CANNTG motifs essentially eliminated the -295 promoter activity. A construct containing the G-box and CACCTG motif resulted in a transcriptional level that is much greater than the sum of the transcriptional levels from the individual cis-elements, demonstrating that the G-box and CACCTG act synergistically. Substitution mutations of two AT-rich sequences, to which a nuclear protein AG-1 binds, showed that these sites function as major negative (-376/-367, -356/-347) or positive (-191/-182) cis-elements, and that the effect of the two AG-1 binding sites was counteractive in the -391 promoter. These results indicate that the three CANNTG motifs and two AG-1-binding sites play critical roles in transcription of the beta-phaseolin gene in cotyledons.

Base Sequence↗

PubMed1994

[A case of unroofed coronary sinus with persistent left superior vena cava].

A 44-year-old female with left to right shunt and persistent left superior vena cava (PLSVC) suspected of unroofed coronary sinus defect with patent right SVC and innominate vein was treated surgically. PLSVC was ligated and coronary sinus ostium was closed with a EPTFE patch. Roof defect of coronary sinus was left open and allowed the coronary venous blood to drain into the left atrium. Patient recovered well and post-operative cardiac catheterization revealed no significant right to left shunt nor desaturation of arterial blood. In the correction of unroofed coronary sinus defect and PLSVC and no other intra-cardiac defect, ligation of PLSVC and closure of coronary sinus ostium was simple and effective, although it was not anatomically corrected.

Adult↗

PubMed1993

Phytochrome-regulated expression of the genes encoding the small GTP-binding proteins in peas.

We examined the effect of light on the mRNA levels of 11 genes (pra1-pra9A, pra9B, and pra9C) encoding the small GTP-binding proteins that belong to the ras superfamily in Pisum sativum. When the dark-grown seedlings were exposed to continuous white light for 24 hr, the levels of several pra mRNAs in the pea buds decreased: pra2 and pra3 mRNAs decreased markedly; pra4, pra6, and pra9A mRNAs decreased slightly; the other 6 pra mRNAs did not decrease. We studied the kinetics of mRNA accumulation for pra2, pra3, and pra9B in detail during white light illumination and compared them with those of the phytochrome gene and the small subunit gene of ribulose bisphosphate carboxylase: mRNA levels of pra2 and pra3 decreased in a manner similar to that of phytochrome while that of the small subunit increased as was expected. The decreases were triggered by a 2-min monochromatic red light (660 nm) irradiation. The effect of red light was reversed by subsequent exposure to far-red light, indicating an involvement of phytochrome as a photoreceptor in this light-regulated event. This work reports negative regulation of mRNA levels of small GTP-binding proteins by light, mediated by phytochrome.

Journal Article↗

PubMed1993

The tonotopic representation in the auditory cortex of the guinea pig with optical recording.

We examined spatio-temporal characteristics of the tonotopic representation in the auditory cortex of the anesthetized guinea pig with a multichannel optical method using voltage-sensitive dye. The response latencies increased, and the response field in the cortex became small when the stimulus intensity levels were decreased. Low frequencies were represented rostrally and high frequencies caudally. The two fields responding to different frequencies at higher intensity levels gradually overlapped as time after stimulus onset increased, though these response field did not overlap at the beginning of the response. These findings indicate that tonotopic representation varies dynamically with time after stimulus onset.

Acoustic Stimulation↗

PubMed1993

Cronkhite-Canada syndrome associated with colon cancer: report of a case.

A 68-year-old man with the clinical features of Cronkhite-Canada syndrome developed cancer of the ascending colon. Although Cronkhite-Canada syndrome has always been considered a benign condition, it may be a premalignant disorder, as suggested by the clinical course of the patient whose case is described herein.

Adenocarcinoma, Mucinous↗

PubMed1993

Strategies for selecting mutation sites for methionine enhancement in the bean seed storage protein phaseolin.

The complete three-dimensional structure of the bean seed storage protein phaseolin was generated from alpha-carbon coordinates by using molecular mechanic calculations. This structure was used as a template to simulate modifications aimed at increasing the methionine content of phaseolin. A hydrophilic, methionine-rich looping insert sequence was designed. Simulated mutagenesis shows that the insert might be accommodated in turn and loop regions of the protein, but not within an alpha-helix. Methionine content was also increased by the replacement of hydrophobic amino acids with methionine in the central core beta-barrels of the phaseolin protein. Calculations indicated that methionine can effectively replace conserved or variant leucine, isoleucine, and valine residues. However, alanine residues were much more sensitive to substitution, and demonstrated high variability in the effects of methionine replacement. Introduction of multiple substitutions in the barrel interior demonstrated that the replaced residues could interact favorably to relieve local perturbations caused by individual substitutions. Molecular dynamics simulations were also utilized to study the structural organization of phaseolin. The calculations indicate that there are extensive packing interactions between the major domains of phaseolin, which have important implications for protein folding and stability. Since the proposed mutant proteins can be produced and studied, the results presented here provide an ideal test to determine if there is a correlation between the effects obtained by computer simulation and the effects of the mutations on the protein structure expressed in vivo.

Amino Acid Sequence↗

PubMed1993

5' distal and proximal cis-acting regulator elements are required for developmental control of a rice seed storage protein glutelin gene.

Using a homologous transgenic rice system it is demonstrated that 5' distal and proximal cis-acting transcriptional regulatory elements are required for developmental control of a rice seed storage protein glutelin gene. Analyses of gene expression of nine progressively truncated 5' promoter sequences in developing endosperm indicated the existence of at least one major positive element located from the -5.1 to -1.8 kb region. The functional importance of proximal elements in the context of 1.8 kb promoter was demonstrated by single substitution mutations in the TATA box (-28/-23), AACA motif (-73/-61), and protein-binding boxes I (-103/-86), II (-124/-110), III (-175/-158) and IV (-200/-217). A simultaneous mutation of five protein-binding sites (-410/-86) essentially eliminated the activity of the 1.8 kb promoter. Although temporal control of the Gt1 gene during endosperm development was retained in plants of constructs from -5.1 kb to -155 bp, spatial control of the glutelin gene was altered when the 5.1 kb promoter was deleted to -507 bp or -154 bp as the reporter gene activities of these constructs were detected in phloem of leaves, and in stems, sheaths and roots of plants.

Base Sequence↗

PubMed1993

Isolation and characterization of cDNAs that encode eleven small GTP-binding proteins from Pisum sativum.

Eleven cDNA clones (pra1 to pra9A, pra9B, and pra9C) were isolated from a pea (Pisum sativum) leaf cDNA library which were similar to small GTP-binding proteins. These cDNAs encoded proteins of 22-25 kDa, which exhibited 45-92% identity to one another at the amino acid level. The putative proteins included the characteristic sequences of ras-related small GTP-binding proteins: four conserved domains involved in binding of GTP/GDP; an effector domain; and cysteine residues at the COOH-terminus. Indeed, the pra6 protein, expressed in Escherichia coli, clearly showed GTP-binding activity. Phylogenetic analysis showed that these clones can be classified into two subgroups: proteins encoded by pra1 to pra7 being related to ypt3 and rab11 proteins; and proteins encoded by pra8, pra9A, pra9B, and pra9C being related to YPT1 and rab1 proteins. The effector sequences in these two subgroups were different. RNA gel blot analysis showed that most of the corresponding genes are differentially expressed in pea leaves and roots. Variations in expression were also observed for structurally related genes.

Amino Acid Sequence↗

PubMed1993

Spatiotemporal observation of guinea pig auditory cortex with optical recording.

The spatiotemporal characteristics of neural activity in the guinea pig auditory cortex were studied in order to clarify neural processing and coding mechanisms of complex sounds. We used a multi-channel optical recording system for a voltage-sensitive dye: RH795. The experimental results showed that a boomerang-shaped moving pattern of optical response appeared on the cortical surface in response to complex sounds (clicks) stimulation, but a rather fixed pattern appeared in response to tone burst stimulation. The tonotopical organization observed using microelectrode was not directly visible, but a similar topographic pattern was evidenced by selecting regions of a strong response evoked by tone-bursts. The correlative functions of regionwide responses may indicate a parallel and serial neural processing structure.

Acoustic Stimulation↗

PubMed1993

[Primary chylopericardium: a case report].

A case of primary chylopericardium in a 54 year-old-man was reported. Despite 3 times of pericardiocentesis, the pericardial fluid accumulated rapidly. After the fenestration of pericardium, a small cannula was inserted for the thoracic ductgram which showed a clearly visible duct upward to the angulus venosus and an abnormal branch near the bifurcation of the trachea spilling some contrast material into the pericardial cavity. Ligation and division of the thoracic duct including an abnormal branch was performed from its entry to the thorax for a length of 13 cm upward. The postoperative course was uneventful and chest X-ray film taken 6 months after surgery showed no accumulation of chyle in the pericardium and pleural cavity.

Chyle↗

PubMed1992

Dynamic characteristics of the auditory cortex of guinea pigs observed with multichannel optical recording.

The spatiotemporal characteristics of neural activity in the guinea pig auditory cortex are investigated to determine their importance in neural processing and coding of the complex sounds. A multi-channel optical recording system has been developed for observing the cortical field of the mammalian brain in vivo. Using the voltage-sensitive dye: RH795, optical imaging was used to visualize neural activity in the guinea pig auditory cortex. Experimental results reveal a boomerang-shaped pattern of movement of activated neural cell regions for the evoked response to click as complex sounds. Parallel and sequential neural processing structure was observed. Although the exact frequency selectivities of single cells and tonotopical organization observed using microelectrode were not visible, the similar feature to the microelectrode evidences was imaged by extracting the strongly response field from the optical data.

Acoustic Stimulation↗

PubMed1992

Biophysical analysis of phaseolin denaturation induced by urea, guanidinium chloride, pH, and temperature.

The structural stability of phaseolin was determined by using absorbance, circular dichroism (CD), fluorescence emission, and fluorescence polarization anisotropy to monitor denaturation induced by urea, guanidinium chloride (GdmCl), pH changes, increasing temperature, or a combination thereof. Initial results indicated that phaseolin remained folded to a similar extent in the presence or absence of 6.0 M urea or GdmCl at room temperature. In 6.0 M GdmCl, phaseolin denatures at approximately 65 degrees C when probed with absorbance, CD, and fluorescence polarization anisotropy. The transition occurs at lower temperatures by decreasing pH. Kinetic measurements of denaturation using CD indicated that the denaturation is slow below 55 degrees C and is associated with an activation energy of 52 kcal/mol in 6.0 M GdmCl. In addition, kinetic measurement using fluorescence emission indicated that the single tryptophan residue was sensitive to at least two steps of the denaturation process. The fluorescence emission appeared to reflect some other structural perturbation than protein denaturation, as fluorescence inflection occurred approximately 5 degrees C prior to the changes observed in absorbance, CD, and fluorescence polarization anisotropy.

Circular Dichroism↗

PubMed1992

Four distinct nuclear proteins recognize in vitro the proximal promoter of the bean seed storage protein beta-phaseolin gene conferring spatial and temporal control.

A proximal promoter (-422/-13) of the bean seed storage protein beta-phaseolin gene contains cis-regulatory elements conferring spatial and temporal gene regulation. To correlate trans-acting elements with these cis-elements, we performed gel mobility shift and exonuclease III protection assays using bean seed nuclear proteins, and identified target sequences of four DNA-binding proteins associated with this promoter. Three CANNTG motifs, CACGTG (-248/-243), CACCTG (-163/-158), and CATATG (-100/-95), were determined as target sequences of the same DNA-binding protein designated CAN. Competition assays using oligonucleotides containing the wild-type or mutated CANNTG motif indicated that the CANNTG motif appears to be a preferred target sequence for CAN binding. Competition assays also demonstrated that DNA-binding protein AG-1 binds to AAAAAG(A/G)CAA (-356/-347, -191/-182), CA-1 binds to two CA-rich sequences (-201/-192, -175/-160), and that a TATA-box binding protein binds to either TATATAA (-43/-37) or TATAAA (-32/-27) or both. Based on these and other results, it is proposed that CACGTG motif (-248/-243) is a major cis-acting regulatory element conferring spatial and temporal control of the beta-phaseolin gene.

Base Sequence↗

PubMed1992

A Sulfonylurea Herbicide Resistance Gene from Arabidopsis thaliana as a New Selectable Marker for Production of Fertile Transgenic Rice Plants.

A mutant acetolactate synthase (ALS) gene, csr1-1, isolated from sulfonylurea herbicide-resistant Arabidopsis thaliana, was placed under control of a cauliflower mosaic virus 35S promoter (35S). Rice protoplasts were transformed with the 35S/ALS chimeric gene and regenerated into fertile transgenic rice (Oryza sativa) plants. The 35S/ALS gene was expressed effectively as demonstrated by northern blot hybridization analysis, and conferred to transformed calli at least 200-fold greater chlorsulfuron resistance than nontransformed control calli. Effective selection of 35S/ALS-transformed protoplasts was achieved at extremely low chlorsulfuron concentrations of 10 nm. The results demonstrated that the 35S/ALS gene is an alternative selectable marker for rice protoplast transformation and fertile transgenic rice production. The results also suggest that the mutant form of Arabidopsis ALS enzyme operates normally in rice cells. Thus, the mechanism of protein transport to chloroplast and ALS inhibition by chlorsulfuron is apparently conserved among plant species as diverse as Arabidopsis (dicotyledon) and rice (monocotyledon).

Journal Article↗

PubMed1992

The use of t-butyl alcohol in the microdissection of resin corrosion casts for SEM.

We developed a new method using t-butyl alcohol in the microdissection of microvascular resin casts of the rat cerebral cortex for scanning electron microscopy. Brains injected with Mercox resin were eroded with sodium hypochlorite solution and dehydrated with graded ethanol. The resin casts obtained were embedded and frozen in t-butyl alcohol at 4 degrees C, and shaved through the planes of interest parallel to the brain surface with a razor blade. The sections were directly freeze-dried and coated with gold and platinum for scanning electron microscopy. Our method enables the demonstration of cross sections of the fine microvascular networks by SEM without any contamination or mechanical artifacts such as distortion and destruction.

Animals↗

PubMed1992

[Oculomotor nerve palsy due to small midbrain infarct--functional topography based on MRI findings].

This is a report of 3 cases presented with oculomotor nerve palsy caused by small midbrain infarct. The aim of this report is to clarify the functional topography of intranuclear and intrafascicular portion of the oculomotor nerve with MRI. Three cases are 2 males and 1 female, ranging 51 to 68 years in age. Except for the long tract signs at the acute stage, cardinal sings were all eye-related, incomplete in 1 case and pupil sparing-type in 2 cases. In MRI, the size of the lesion extended 5 to 12 mm. In the incomplete palsy case, the infarction extended from the level immediately below the 3rd ventricle into the whole length of midbrain, whereas in the pupil-sparing types, more limited lesion excluding the upper part of the midbrain was noted. Anatomically the longitudinal size of the nucleus is 10mm and nerves functionally related to pupil reaction, eye motion and eyelid elevation are arranged in rosrocaudal order. Therefore, it is speculated that in midbrain, intrafascicular location of nerve fibers associated with pupil reaction is rostral and oculomotor nerve palsy of pupil sparing type is caused by the lesion excluding the rostral midbrain. MRI findings of the present 3 cases are compatible with this speculation. The lowest border of red nucleus is at the level of superior colliculus, whereas oculomotor nucleus has its lowest margin at the inferior colliculus. Therefore, red nucleus becomes an informative landmark to visualized the level of oculomotor nerve injury, since the red nucleus is clearly demonstrated in high intensity in T2 weighted image.

Aged↗

PubMed1991

Transposition of the maize activator element in transgenic rice plants.

Transposition of the maize Activator (Ac) element was observed in transgenic rice. After protoplast transformation, Ac excision from an interrupted hygromycin phosphotransferase gene was monitored by appearance of the hygromycin-resistant colonies. The frequency of Ac excision, based on the biological assay was up to 19%. Southern hybridization analysis indicated that at least one copy per genome of the hygromycin-resistance gene was reconstituted after Ac excision and that the transposed Ac element was reintegrated into the rice genome. Analysis of DNA sequences at 14 empty donor sites indicated that the Ac element was excised in rice in a similar manner as maize. The excision of an Ac mutant in which a 1.3 kbp Tn903 fragment was inserted at a unique BamHI site so as to disrupt binding of the putative transposase was not detected by DNA analysis. These results demonstrated that the maize Ac element might be used as an effective heterologous transposon for mutagenesis and gene tagging in rice, an important food crops.

Base Sequence↗